A continuous-flow aerobic granular sludge process for wastewater treatment

Abstract

The present application provides a kind of continuous flow aerobic granular sludge process system, granular sludge section, flocculent sludge section are sequentially provided along the water inlet direction, the granular sludge section is sequentially provided with sludge-water contact zone, granular sludge biochemical reaction zone along the water inlet direction, the region close to flocculent sludge section in granular sludge biochemical reaction zone is equipped with sludge screen, and the flocculent sludge section includes flocculent sludge biochemical reaction zone.The present application also provides a kind of continuous flow aerobic granular sludge method sewage treatment method.The present application provides a kind of continuous flow aerobic granular sludge method sewage treatment method, can realize sludge granulation of front stage efficiently and quickly, can also ensure that sewage treatment effect is not reduced in granulation process, and comprehensive sewage treatment capacity and treatment effect will be improved than before modification, shorten reaction time, reduce land occupation, reduce construction cost.

Description

Technical Field

[0001] This invention belongs to the technical field of wastewater treatment, and relates to a continuous flow aerobic granular sludge wastewater treatment method, specifically to a continuous flow aerobic granular sludge wastewater treatment device and method for wastewater treatment. Background Technology

[0002] In recent years, aerobic granular sludge wastewater biological treatment technology has attracted widespread attention due to its higher treatment efficiency and better sludge settling performance compared to traditional flocculent sludge biological treatment systems, and has been widely used in engineering projects abroad.

[0003] Currently, the sequencing batch reactor (SBR) is mainly used to implement the engineering application of aerobic granular sludge technology. This means the biochemical reaction process is carried out in batches, with each batch typically consisting of three stages: reaction, sedimentation, and influent-effluent. The SBR can conveniently create two basic conditions for the growth of aerobic granular sludge: firstly, the selective screening of flocculent sludge (or light sludge), and secondly, the preferential supply of nutrients (preferential feeding) to granular sludge (or heavy sludge).

[0004] However, actual wastewater biological treatment systems are mainly continuous flow systems, such as the AAO process, multi-stage AO process, and Bardenpho process widely used in municipal wastewater treatment plants, as well as aerobic biological processes and AO processes used in industrial wastewater treatment. Converting existing continuous flow wastewater biological treatment processes into sequencing batch reactor (SBR) processes requires extremely high investment and is difficult to implement.

[0005] Some researchers have adopted a bypass aerobic granular sludge generator to achieve a certain degree of sludge granulation based on existing continuous-flow wastewater biological treatment processes. For example, a bypass cyclone separator or high-load settler can be used to separate light and heavy sludge. The separated light sludge is discharged from the treatment system, while the heavy sludge is returned. This creates the selective pressure condition, one of the basic conditions for the formation of aerobic granular sludge. After a long period of selective washing, a small amount of granular sludge will appear in the main biological system. However, this method of sludge granulation has three problems: first, the cultivation time is long, often requiring more than six months to reach a certain degree of granulation; second, the degree of granulation is low, often only reaching about 20% in municipal wastewater applications; and third, in the early stages of cultivation, the loss of light sludge can cause an excessive decrease in the sludge concentration in the biological system, affecting the wastewater treatment effect. Summary of the Invention

[0006] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a continuous flow aerobic granular sludge wastewater treatment method. Through optimized structure, treatment steps and conditions, the biochemical treatment efficiency is greatly improved, thereby shortening the reaction time, reducing the land area and construction costs.

[0007] To achieve the above and other related objectives, the first aspect of the present invention provides a continuous flow aerobic granular sludge process system, which includes a granular sludge section and a flocculent sludge section arranged sequentially along the influent direction. The granular sludge section is provided with a sludge-water contact zone and a granular sludge biochemical reaction zone arranged sequentially along the influent direction. A sludge screen is provided in the area of ​​the granular sludge biochemical reaction zone near the flocculent sludge section. The flocculent sludge section includes the flocculent sludge biochemical reaction zone.

[0008] A second aspect of the present invention provides a continuous flow aerobic granular sludge wastewater treatment method, employing the continuous flow aerobic granular sludge process system provided in the first aspect of the present invention, comprising the following steps:

[0009] 1) After the wastewater is introduced into the mud-water contact zone of the granular sludge section, it is then introduced into the granular sludge biochemical reaction zone of the granular sludge section. Under the action of the sludge screener, the wastewater undergoes the first separation to obtain the first heavy sludge.

[0010] 2) The first heavy sludge is returned to the sludge-water contact zone to react with the sewage to form the first mixed liquor;

[0011] 3) After the first mixed liquor is introduced into the granular sludge biochemical reaction zone for the first biochemical reaction, it is then separated for the second time under the action of the sludge screener to obtain the second heavy sludge and light sludge.

[0012] 4) Repeat steps 2) to 3) with the second heavy sludge, perform the first circulation reflux, and then discharge the excess heavy sludge;

[0013] 5) The second mixture formed by light sludge and sewage is introduced into the flocculent sludge biochemical reaction zone of the flocculent sludge section for a second biochemical reaction. After solid-liquid separation in the sedimentation zone, clear liquid and residual light sludge are obtained, and the clear liquid is discharged.

[0014] 6) Return the residual light sludge to the flocculent sludge biochemical reaction zone, repeat step 5), and discharge the excess light sludge after the second cycle of return.

[0015] As described above, the continuous flow aerobic granular sludge wastewater treatment method provided by the present invention has the following beneficial effects:

[0016] (1) The present invention provides a continuous flow aerobic granular sludge wastewater treatment method, which, after modification of the existing wastewater biological treatment system, can efficiently and quickly achieve sludge granulation in the front stage, with most pollutants being efficiently degraded by the granular sludge; and can also ensure that the wastewater treatment effect is not reduced during the granulation process. After the sludge granulation reaches the designed level, the overall wastewater treatment capacity and treatment effect will be improved compared with before the modification.

[0017] (2) The continuous flow aerobic granular sludge wastewater treatment method provided by the present invention is simple to design for new projects, greatly improves the biochemical treatment efficiency, thereby shortening the reaction time, reducing the land area and reducing the construction cost. Attached Figure Description

[0018] Figure 1 The diagram shows the flow structure of a continuous flow aerobic granular sludge process system using a sedimentation tank.

[0019] Figure 2 The diagram shows the flow structure of a continuous flow aerobic granular sludge process system with an integrated settler.

[0020] Figure 3 The diagram shows the flow structure of a continuous flow aerobic granular sludge process system using a membrane bioreactor (MBR).

[0021] Figure Labels

[0022] 1 Granular sludge section

[0023] 11 Mud-water contact area

[0024] 12 Granular sludge biochemical reaction zone

[0025] 13 Sludge Screener

[0026] 14 First reflux pipe

[0027] 15 First Discharge Pipe

[0028] 2. Flocculent sludge section

[0029] 21. Flocculent sludge biochemical reaction zone

[0030] 22 Sedimentation Zone

[0031] 221 Sedimentation Tank

[0032] 222 Sedimenter

[0033] 223 Membrane Filter

[0034] 23 Second reflux pipe

[0035] 24 Second Discharge Pipe

[0036] 25 Third reflux pipe

[0037] 26 Third Discharge Pipe

[0038] 3. Water inlet pipe

[0039] 4. Water outlet pipe

[0040] 5. Concurrent flow pipe Detailed Implementation

[0041] Please see Figures 1 to 3 It should be understood that the structures, proportions, sizes, etc., illustrated in the accompanying drawings are merely for illustrative purposes to aid those skilled in the art and to facilitate understanding and reading. They are not intended to limit the scope of the invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of the invention, should still fall within the scope of the technical content disclosed in this invention. Furthermore, the terms such as "upper," "lower," "left," "right," "middle," and "one" used in this specification are merely for clarity and not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention's implementation.

[0042] The first aspect of this invention provides a continuous flow aerobic granular sludge process system, such as... Figure 1-3 As shown, a granular sludge section and a flocculent sludge section are arranged sequentially along the water inlet direction. The granular sludge section is provided with a sludge-water contact zone and a granular sludge biochemical reaction zone along the water inlet direction. A sludge screen is provided in the area of ​​the granular sludge biochemical reaction zone near the flocculent sludge section. The flocculent sludge section includes the flocculent sludge biochemical reaction zone.

[0043] In the above system, such as Figure 1-3 As shown, the mud-water contact area is connected to a water inlet pipe.

[0044] In the above system, such as Figure 1-3 As shown, the mud-water contact zone is an anaerobic reaction unit.

[0045] In one embodiment, the anaerobic reaction unit is an anaerobic reaction tank or an anaerobic reactor.

[0046] The mud-water contact zone is a reaction zone in which the returned heavy sludge, i.e., granular sludge, comes into full contact with the incoming wastewater.

[0047] In the above system, such as Figure 1-3As shown, the granular sludge biochemical reaction zone is selected from one of an aerobic reaction unit or a combined reaction unit. The combined reaction unit includes an aerobic reaction unit and other reaction units, and the other reaction units are selected from at least one of an anaerobic reaction unit or an anoxic reaction unit.

[0048] In one embodiment, the aerobic reaction unit is an aerobic reaction tank or an aerobic reactor.

[0049] In one embodiment, the anaerobic reaction unit is an anaerobic reaction tank or an anaerobic reactor.

[0050] In one embodiment, the anoxic reaction unit is an anoxic reaction tank or anoxic reactor.

[0051] The granular sludge biochemical reaction zone is the site where the biochemical reactions that degrade pollutants by microorganisms in the granular sludge occur.

[0052] In the above system, such as Figure 1-3 As shown, the sludge screener is the sedimentation device described in patent application "2024116206648 A sedimentation device and its biological treatment tank and sewage treatment method".

[0053] The sieving action of the sludge screener creates a "selective pressure screening" condition, which keeps heavy sludge in the granular sludge biochemical reaction zone of the granular sludge section, while light sludge is eliminated from the granular sludge section. Meanwhile, the sewage enters from the mud-water contact zone at the front end of the granular sludge section. The pollutants in the sewage are nutrients for the growth of microorganisms, so the granular sludge preferentially utilizes the nutrients, creating a "preferred feeding" condition. The light sludge can only utilize the few remaining nutrients in the flocculent sludge biochemical reaction zone of the subsequent flocculent sludge section, thereby inhibiting the competitive growth of light sludge.

[0054] In the above system, such as Figure 1-3 As shown, the sludge screener is connected to the inlet end of the sludge-water contact zone via a first return pipe to realize the return of heavy sludge, i.e. granular sludge. The sludge screener is also connected to a first discharge pipe.

[0055] In one implementation, such as Figure 1-3 As shown, the first return pipe passes through the granular sludge biochemical reaction zone and connects to the sludge-water contact zone. This is used to achieve the recycling and return of heavy sludge, i.e., granular sludge, which is then enriched within the granular sludge biochemical reaction zone.

[0056] In one implementation, such as Figure 1-3 As shown, the first discharge pipe passes through the granular sludge biochemical reaction zone, and the outlet of the first discharge pipe is located outside the granular sludge biochemical reaction zone. It is used to discharge excess heavy sludge generated by the growth and proliferation of microorganisms.

[0057] The flocculent sludge biochemical reaction zone is the site where the biochemical reactions of microorganisms in the flocculent sludge degrade pollutants.

[0058] In the above system, such as Figure 1-3 As shown, the flocculent sludge biochemical reaction zone is selected from at least one of an aerobic reaction unit, an anaerobic reaction unit, or an anoxic reaction unit.

[0059] In one embodiment, the aerobic reaction unit is an aerobic reaction tank or an aerobic reactor.

[0060] In one embodiment, the anaerobic reaction unit is an anaerobic reaction tank or an anaerobic reactor.

[0061] In one embodiment, the anoxic reaction unit is an anoxic reaction tank or anoxic reactor.

[0062] The flocculent sludge biochemical reaction zone of the flocculent sludge section supplements the pollutant degradation effect of the granular sludge section. Especially in the initial stage of sludge screening, when the granular sludge growth in the granular sludge section is insufficient and the treatment effect is inadequate, a higher proportion of the remaining pollutants enter the flocculent sludge biochemical reaction zone of the flocculent sludge section, and the pollutants are further degraded.

[0063] In the above system, such as Figure 1-3 As shown, the flocculent sludge section also includes a sedimentation zone, which is located within the flocculent sludge biochemical reaction zone or connected to the effluent end of the flocculent sludge biochemical reaction zone.

[0064] In one implementation, such as Figure 1-3 As shown, the sedimentation zone is selected from at least one of a sedimentation tank, a sedimentator, or a membrane filter.

[0065] In a preferred embodiment, such as Figure 1 As shown, the sedimentation tank is a secondary sedimentation tank. The secondary sedimentation tank is a conventionally used secondary sedimentation tank.

[0066] In a preferred embodiment, such as Figure 2 As shown, the sedimentation tank is a built-in sedimentation tank. The built-in sedimentation tank is the sedimentation tank form described in patent application "2024116206648 A sedimentation tank and its biological treatment tank and sewage treatment method".

[0067] In a preferred embodiment, such as Figure 3 As shown, the membrane filter is a membrane bioreactor (MBR). The membrane bioreactor is a conventionally used membrane bioreactor (MBR).

[0068] In a preferred embodiment, such as Figure 1 As shown, when the sedimentation zone is a sedimentation tank, the sedimentation tank is connected to the effluent end of the flocculent sludge biochemical reaction zone.

[0069] In a further preferred embodiment, such as Figure 1 As shown, the sedimentation tank is connected to the effluent end of the flocculent sludge biochemical reaction zone via a co-current pipe.

[0070] In a further preferred embodiment, such as Figure 1 As shown, the sedimentation tank is connected to the inlet of the flocculent sludge biochemical reaction zone via a second return pipe to achieve the circulation and return of flocculent sludge, which is then enriched within the flocculent sludge biochemical reaction zone. The sedimentation tank is also connected to a second discharge pipe. The second discharge pipe is used to discharge excess flocculent sludge produced by the growth and proliferation of microorganisms.

[0071] In a preferred embodiment, such as Figure 2-3 As shown, when the sedimentation zone is a sedimentator or membrane filter, the sedimentator or membrane filter is located in the area near the effluent end of the flocculent sludge biochemical reaction zone.

[0072] In a further preferred embodiment, such as Figure 2-3 As shown, the flocculent sludge biochemical reaction zone is connected to a third return pipe and a third discharge pipe. The third return pipe is connected to the inlet and outlet of the flocculent sludge biochemical reaction zone to realize the return of flocculent sludge, which is then enriched within the flocculent sludge biochemical reaction zone. One end of the third discharge pipe is connected to the flocculent sludge biochemical reaction zone to discharge excess flocculent sludge produced by the growth and proliferation of microorganisms.

[0073] In one implementation, such as Figure 1-3 As shown, the outlet end of the sedimentation zone is connected to an outlet pipe.

[0074] A second aspect of the present invention provides a continuous flow aerobic granular sludge wastewater treatment method, employing the continuous flow aerobic granular sludge process system provided in the first aspect of the present invention, comprising the following steps:

[0075] 1) After the wastewater is introduced into the mud-water contact zone of the granular sludge section, it is then introduced into the granular sludge biochemical reaction zone of the granular sludge section. Under the action of the sludge screener, the wastewater undergoes the first separation to obtain the first heavy sludge.

[0076] 2) The first heavy sludge is returned to the sludge-water contact zone to react with the sewage to form the first mixed liquor;

[0077] 3) After the first mixed liquor is introduced into the granular sludge biochemical reaction zone for the first biochemical reaction, it is then separated for the second time under the action of the sludge screener to obtain the second heavy sludge and light sludge.

[0078] 4) Repeat steps 2) to 3) with the second heavy sludge, perform the first circulation reflux, and then discharge the excess heavy sludge;

[0079] 5) The second mixture formed by light sludge and sewage is introduced into the flocculent sludge biochemical reaction zone of the flocculent sludge section for a second biochemical reaction. After solid-liquid separation in the sedimentation zone, clear liquid and residual light sludge are obtained, and the clear liquid is discharged.

[0080] 6) Return the residual light sludge to the flocculent sludge biochemical reaction zone, repeat step 5), and discharge the excess light sludge after the second cycle of return.

[0081] In step 1), the wastewater is introduced into the mud-water contact area through the inlet pipe.

[0082] In step 1), during the first separation, the sludge separation load of the sludge screen is 3 to 10 m³ / h.

[0083] In step 2), as Figure 1-3 As shown, the first heavy sludge is returned to the inlet end of the sludge-water contact zone via the first return pipe.

[0084] In step 2), the reaction time of the mud-water contact reaction is 1-3 hours.

[0085] In step 2), the mud-water contact reaction is carried out by stirring and mixing, and the stirring method is selected from mechanical stirring or air stirring. This allows the mud and water to be fully mixed and reacted in the mud-water contact zone to form a first mixed liquid, which is used to inhibit the growth of flocculent sludge.

[0086] During the formation of the first mixed liquor, the wastewater enters the wastewater contact zone of the granular sludge section and comes into contact with the returned first heavy sludge (i.e., returned granular sludge). Since the sludge screening function of the sludge screener is mainly granular sludge, the granular sludge preferentially utilizes the nutrients in the influent, avoiding competition for nutrients by the flocculent sludge. This creates preferential feeding conditions for the growth of granular sludge and inhibits the growth of flocculent sludge.

[0087] In step 3), the first biochemical reaction is selected from one of aerobic reaction or combined reaction, the combined reaction including aerobic reaction and other reactions, and the other reactions are selected from at least one of anaerobic reaction or hypoxic reaction.

[0088] The first biochemical reaction refers to the biodegradation of pollutants in wastewater by microorganisms in the granular sludge within the granular sludge biochemical reaction zone. This first biochemical reaction can be a single aerobic reaction, or a combination of anaerobic and aerobic reactions, anoxic and aerobic reactions, anaerobic and anoxic reactions, or anaerobic and aerobic reactions, etc.

[0089] In step 3), during the second separation, the sludge separation load of the sludge screen is 3–10 m³ / h. Based on the settling velocity (selective pressure), i.e., selective pressure washing, light sludge in the sludge has a poor settling velocity, while heavy sludge has a good settling velocity. Heavy sludge exceeding the sludge screen's separation load will not be discharged with the effluent from the sludge screen and will remain in the granular sludge section; light sludge below the sludge screen's separation load will be discharged with the effluent from the sludge screen, eliminated from the granular sludge section, and enter the subsequent flocculent sludge section.

[0090] The aforementioned sludge screener serves as a means of separating light and heavy sludge within the biochemical reaction tank, creating selective pressure screening conditions. The sludge screener divides the biochemical reaction process into two stages: a granular sludge stage (heavy sludge stage) and a flocculent sludge stage (light sludge stage). The granular sludge in the first stage preferentially contacts and utilizes nutrients, thus creating preferential feeding conditions for the granular sludge. At the same time, the flocculent sludge stage retains a high concentration of flocculent sludge, ensuring the wastewater treatment effect during the granulation cultivation process.

[0091] The first mixed liquor enters the sludge screener for separation, which creates selective pressure screening conditions for the sludge. Specifically, light sludge with settling properties lower than the selective pressure of the screen flows out of the sludge screener with the wastewater to the subsequent flocculent sludge section; heavy sludge with settling properties higher than the selective pressure of the screen, that is, large-particle sludge, is not carried out by the effluent of the sludge screener and is retained in the granular sludge section, forming a mixture and circulation within the granular sludge section. Excess heavy sludge due to microbial growth and proliferation is discharged from the system as excess granular sludge.

[0092] In step 4), the excess heavy sludge is discharged through the first discharge pipe.

[0093] In step 5), the second biochemical reaction is selected from at least one of aerobic reaction, anaerobic reaction, or hypoxic reaction.

[0094] The second biochemical reaction can be a single aerobic reaction, anaerobic reaction, or hypoxic reaction, or it can be a combination of "anaerobic + aerobic", "hypoxic + aerobic", "anaerobic + hypoxic", "anaerobic + hypoxic + aerobic", or "anaerobic + aerobic + hypoxic", etc.

[0095] In step 5), as Figure 1-3 As shown, the clear liquid is discharged through the outlet pipe.

[0096] In step 6), as Figure 1-3 As shown, the residual light sludge is returned to the inlet end of the flocculent sludge biochemical reaction zone via the second or third return pipe.

[0097] In step 6), as Figure 1-3 As shown, the excess light sludge is discharged through the second discharge pipe.

[0098] During the second biochemical reaction and the second recycling process, the wastewater and light sludge flowing out of the sludge separator form a second mixed liquor. The biochemical reaction continues in the light sludge section. The flocculent sludge biochemical reaction zone can be divided into anaerobic, anoxic, and aerobic zones, or a combination of several reaction forms, as needed. After being treated in the flocculent sludge biochemical reaction zone, the wastewater carrying the sludge is separated into solid and liquid phases by a sedimentation tank, sedimentator, or membrane filter. The clear liquid is discharged from the system, and the light sludge is recycled to form a cycle. The excess light sludge due to the growth and proliferation of microorganisms is discharged from the system in the form of excess flocculent sludge.

[0099] This method highlights two innovative conditions for granular sludge: "selective pressure screening" and "preferred" feeding. Specifically, in the system described above, an internal screening device is added to achieve "light-heavy" sludge separation, thereby dividing the biochemical reaction process into two parts—a granular sludge reaction section and a flocculent sludge reaction section. This utilizes the high efficiency of granular sludge while ensuring that the subsequent flocculent sludge section supplements the reaction effect, preventing insufficient treatment during sludge granulation.

[0100] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0101] Comparative Example 1

[0102] A municipal wastewater treatment plant in Zhejiang Province has a designed capacity of 20,000 m³. 3 / d, the treated water complies with the local discharge standards of Zhejiang Province, and the wastewater biological treatment system adopts the traditional AAO continuous flow activated sludge biological treatment process (anaerobic + anoxic + aerobic + secondary sedimentation tank) system.

[0103] Based on the designed water volume, the existing process has a hydraulic retention time of 2 hours in the anaerobic reactor, 6 hours in the anoxic reactor, and 8 hours in the aerobic reactor, for a total of 16 hours of biochemical hydraulic retention time. The surface loading of the secondary sedimentation tank is 1.0 m³ / h.

[0104] This wastewater biological treatment system lacks sludge granulation enhancement measures, and the sludge in the system exists in a flocculent sludge form. This system suffers from drawbacks such as low pollutant degradation efficiency, low biochemical denitrification efficiency, low utilization rate of its own carbon source, poor sludge settling performance, and large sludge production volume.

[0105] During the rainy season, the wastewater treatment plant's maximum hourly treatment capacity is only 1100 cubic meters. 3 / h; In non-winter seasons (when the water temperature entering the biological treatment system is above 15℃), the total nitrogen in the secondary sedimentation tank effluent is 9-12 mg / L and the total phosphorus is 0.6-0.8 mg / L; During winter operation (when the water temperature entering the biological treatment system is below 15℃), the total nitrogen in the secondary sedimentation tank effluent is 10-15 mg / L, and an external carbon source (sodium acetate solution) costing 3,000 yuan per day is needed to ensure that the total nitrogen in the effluent is stable below 12 mg / L (discharge standard); On average throughout the year, the sludge production per 10,000 tons of wastewater is 9 tons (based on sludge with a water content of 80%), and the average cost of sludge treatment and outsourced disposal per ton is 400 yuan.

[0106] Example 1

[0107] Adopting such Figure 1 The continuous flow aerobic granular sludge wastewater biological treatment process shown here involves in-situ modification of the plant's biological system (anaerobic + anoxic + aerobic + secondary sedimentation tank). The main modification measures are: retaining the original anaerobic and anoxic reactors (hereinafter referred to as the pre-anoxic reactors) without modification; dividing the aerobic reactors into three sections: a pre-aerobic reactor (based on the original design flow rate and hydraulic retention time of 3 hours), a post-anoxic reactor (based on the original design flow rate and hydraulic retention time of 3 hours), and a post-aerobic reactor (based on the original design flow rate and hydraulic retention time of 2 hours), thus transforming the biological treatment system into a five-section (AAOAO) system. A sludge screen is added to the post-anoxic reactor. The screen used adopts the sedimentation type described in patent application "2024116206648 A Sedimenter and its Biological Treatment Tank and Wastewater Treatment Method," with a designed sedimentation load of 7.5 m³. 3 / m 2 •h (i.e., the sludge separation load of the screener is 7.5 m³ / h). The anaerobic reactor is used as the sludge-water contact zone. Thus, the anaerobic reactor (sludge-water contact zone), the pre-anoxic reactor, the pre-aerobic reactor, the post-anoxic reactor, the sludge screener, and the corresponding pumps and pipelines constitute the "granular sludge section," of which the pre-anoxic reactor, the pre-aerobic reactor, and the post-anoxic reactor constitute the "granular sludge biological reaction zone." The post-aerobic reactor, together with the original secondary sedimentation tank and the corresponding pumps and pipelines, constitute the "flocculated sludge section," and the post-aerobic reactor is the "flocculated sludge biological reaction zone."

[0108] The specific processing includes the following steps:

[0109] 1) Wastewater is introduced into the mud-water contact zone of the granular sludge section through the inlet pipe, and then introduced into the granular sludge biochemical reaction zone of the granular sludge section through the co-flow pipe. Under the action of the sludge screener, the first separation is carried out. The sludge separation load is 7.5 m / h, and the first heavy sludge is obtained.

[0110] 2) The first heavy sludge is returned to the inlet of the sludge-water contact zone through the first return pipe, and undergoes a sludge-water contact reaction (anaerobic) with the sewage under mechanical stirring for 2 hours to form the first mixed liquor;

[0111] 3) The first mixed liquor is introduced into the granular sludge biochemical reaction zone for the first biochemical reaction (anoxic + aerobic + anoxic), and then separated for the second time under the action of the sludge screener. The sludge separation load is 7.5 m / h, and the second heavy sludge and light sludge are obtained.

[0112] 4) Repeat steps 2) to 3) with the second heavy sludge, and after the first circulation reflux, discharge the excess heavy sludge that is generated due to the growth and proliferation of microorganisms through the first discharge pipe.

[0113] 5) The second mixture formed by light sludge and sewage is introduced into the flocculent sludge biochemical reaction zone of the flocculent sludge section through the co-flow pipe for a second biochemical reaction (aerobic). After that, solid-liquid separation is carried out in the secondary sedimentation tank. The surface loading of the secondary sedimentation tank is 1.0 m / h. Clear liquid and residual light sludge are obtained. The clear liquid is discharged through the effluent pipe.

[0114] 6) The residual light sludge is returned to the flocculent sludge biochemical reaction zone through the second return pipe. Step 5) is repeated, and after the second circulation return, the excess light sludge is discharged through the second discharge pipe.

[0115] Compared with Comparative Example 1, the modified version has the following gain effects:

[0116] 1) Increased capacity: This wastewater treatment plant can handle a larger influent volume, with its maximum hourly treatment capacity increasing to 1800 m³ during the rainy season. 3 / h, which is 64% higher than before the renovation;

[0117] 2) Enhanced efficiency: In non-winter seasons, the total nitrogen in the secondary sedimentation tank effluent is 6-8 mg / L and the total phosphorus is 0.3-0.5 mg / L, resulting in better effluent performance from the biological treatment system; in winter, the total nitrogen in the secondary sedimentation tank effluent is 7-9 mg / L, and no external carbon source is needed to ensure that the total nitrogen in the treated water remains stable below the discharge standard of 10 mg / L.

[0118] 3) Reduced energy consumption: Reduced or even eliminated external carbon source consumption;

[0119] 4) Sludge reduction: On average throughout the year, the sludge production per 10,000 tons of wastewater is 6 tons (based on sludge with a moisture content of 80%), which is 33% lower than before the renovation.

[0120] 5) Improve production reliability: Increased volume and efficiency significantly improve the production reliability of wastewater treatment plants;

[0121] 6) Reduced operating costs: Lowering external carbon source consumption and reducing sludge production both reduce operating costs. After the renovation, the plant saved 3,000 yuan / day in external carbon source costs during winter and 2,400 yuan / day in sludge treatment and disposal costs, for a total saving of 5,400 yuan / day in operating costs.

[0122] Example 2

[0123] A dyeing and printing factory built a new wastewater treatment plant, and the biochemical treatment system adopted the following... Figure 2 The continuous flow aerobic granular sludge wastewater biological treatment process system is shown.

[0124] Designed wastewater treatment capacity: 200m³ 3 The hydraulic retention time in the sludge-water contact zone is 2 hours, and mechanical stirring is used. The granular sludge section's granular sludge biochemical reaction zone consists of an anaerobic tank and a pre-aerobic tank. The hydraulic retention time in both the anaerobic and pre-aerobic tanks is 6 hours. The sludge-water separator adopts the sedimentation type described in patent application "2024116206648 A Sedimenter and its Biochemical Tank and Wastewater Treatment Method," with a separation load of 6 m³ / h. The flocculent sludge section's flocculent sludge biochemical reaction zone consists of a post-aerobic tank. The hydraulic retention time in the post-aerobic tank is 6 hours, and an internal sedimentation tank is used. The sedimentation tank adopts the sedimentation type described in patent application "2024116206648 A Sedimenter and its Biochemical Tank and Wastewater Treatment Method," with a separation load of 2 m³ / h.

[0125] The total hydraulic retention time of the entire biological treatment system is 20 hours (including the time in the sedimentation tank). The old wastewater treatment plant of this dyeing and printing unit used the traditional flocculent activated sludge process, with a total hydraulic retention time of 40 hours (including the time in the secondary sedimentation tank). The efficiency of the new plant's wastewater biological treatment system has doubled, significantly saving on land use and construction costs.

[0126] The specific processing includes the following steps:

[0127] 1) Wastewater is introduced into the mud-water contact zone of the granular sludge section through the inlet pipe, and then introduced into the granular sludge biochemical reaction zone of the granular sludge section through the co-flow pipe. Under the action of the sludge screener, the first separation is carried out. The sludge separation load is 8m / h, and the first heavy sludge is obtained.

[0128] 2) The first heavy sludge is returned to the inlet of the sludge-water contact zone through the first return pipe, and undergoes a sludge-water contact reaction (anaerobic) with the sewage under mechanical stirring for 3 hours to form the first mixed liquor;

[0129] 3) The first mixed liquor is introduced into the granular sludge biochemical reaction zone for the first biochemical reaction (anaerobic + aerobic), and then separated for the second time under the action of the sludge screener. The sludge separation load is 8 m / h, and the second heavy sludge and light sludge are obtained.

[0130] 4) Repeat steps 2) to 3) with the second heavy sludge, and after the first circulation reflux, discharge the excess heavy sludge that is generated due to the growth and proliferation of microorganisms through the first discharge pipe.

[0131] 5) The second mixture formed by light sludge and sewage is introduced into the flocculent sludge biochemical reaction zone of the flocculent sludge section through the co-flow pipe for a second biochemical reaction (aerobic). After solid-liquid separation in the sedimentation zone, clear liquid and residual light sludge are obtained, and the clear liquid is discharged through the effluent pipe.

[0132] 6) The residual light sludge is returned to the flocculent sludge biochemical reaction zone through the second return pipe. Step 5) is repeated, and after the second circulation return, the excess light sludge is discharged through the second discharge pipe.

[0133] Comparative Example 2

[0134] A municipal wastewater treatment plant uses the MBR biological treatment process (anaerobic + anoxic + aerobic + MBR), and other processes and structures are similar to those in Comparative Example 1.

[0135] Example 3

[0136] Adopting such Figure 3 The continuous flow aerobic granular sludge wastewater biological treatment process shown is a modified version of the system structure in Comparative Example 2, while other conditions remain the same as in Example 1. After modification, it was found that the continuous flow aerobic granular sludge process system of this invention can improve the MBR process, and its technical performance is significantly enhanced compared to Comparative Example 2.

[0137] Comparative Examples 3-4

[0138] A newly built wastewater treatment plant employing the same biochemical treatment process as in Example 1 uses a continuous flow aerobic granular sludge wastewater treatment process in its biochemical system. Specific data are shown in Table 1 below. As can be seen from Table 1, only when the treatment conditions conforming to the method of this invention are met does the treatment effect achieve the best results.

[0139] Table 1

[0140] Sludge separation load (m / h) 7.5 2 11 Mud-water contact reaction time (h) 2 4 0.5 Total nitrogen concentration in the effluent from the secondary sedimentation tank (mg / L) ≤10 15 13 Winter external carbon source dosage (mg COD equivalent / L wastewater) / 10 5 Sludge production per 10,000 tons of wastewater (based on sludge with a moisture content of 80%, in tons). 6 8 10 Cost savings on external carbon sources (RMB / day) 3000 1000 2000 Savings in sludge treatment and disposal costs (RMB / day) 2400 1600 800

[0141] In summary, the continuous flow aerobic granular sludge wastewater treatment method provided by this invention can efficiently and rapidly achieve sludge granulation in the upstream stage, while ensuring that the wastewater treatment effect is not reduced during the granulation process. The overall wastewater treatment capacity and effect are improved compared to the previous method, while shortening the reaction time, reducing land occupation, and reducing construction costs. Therefore, this invention effectively overcomes the various shortcomings of existing technologies and has high industrial application value.

[0142] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A continuous flow aerobic granular sludge process system, characterized in that, Along the water inlet direction, there are granular sludge section (1) and flocculent sludge section (2). The granular sludge section (1) is provided with a mud-water contact zone (11) and a granular sludge biochemical reaction zone (12) along the water inlet direction. A sludge screen (13) is provided in the area of ​​the granular sludge biochemical reaction zone (12) near the flocculent sludge section (2). The flocculent sludge section (2) includes a flocculent sludge biochemical reaction zone (21). The mud-water contact zone (11) is an anaerobic reaction unit; The granular sludge biochemical reaction zone (12) is selected from one of an aerobic reaction unit or a combined reaction unit. The combined reaction unit includes an aerobic reaction unit and other reaction units. The other reaction units are selected from at least one of an anaerobic reaction unit or an anoxic reaction unit. The sludge screen (13) is connected to the inlet end of the mud-water contact area (11) via the first return pipe (14), and the sludge screen (13) is also connected to the first discharge pipe (15). The flocculent sludge biochemical reaction zone (21) is selected from at least one of the aerobic reaction unit, anaerobic reaction unit, or anoxic reaction unit; the flocculent sludge section also includes a sedimentation zone (22), which is located in the flocculent sludge biochemical reaction zone (21) or connected to the effluent end of the flocculent sludge biochemical reaction zone (21).

2. The continuous flow aerobic granular sludge process system according to claim 1, characterized in that, The mud-water contact area (11) is connected to a water inlet pipe (3).

3. The continuous flow aerobic granular sludge process system according to claim 1, characterized in that, Includes one or more of the following conditions: A1) The first return pipe (14) passes through the granular sludge biochemical reaction zone (12) and is connected to the sludge-water contact zone (11); A2) The first discharge pipe (15) passes through the granular sludge biochemical reaction zone (12) and the outlet of the first discharge pipe (15) is located outside the granular sludge biochemical reaction zone (12).

4. The continuous flow aerobic granular sludge process system according to claim 1, characterized in that, The precipitation zone (22) includes one or more of the following conditions: B1) The sedimentation zone (22) is selected from at least one of a sedimentation tank, a sedimentator, or a membrane filter; B2) The outlet end of the sedimentation zone (22) is connected to the outlet pipe (4).

5. The continuous flow aerobic granular sludge process system according to claim 4, characterized in that, When the sedimentation zone (22) is a sedimentation tank (221), the sedimentation tank (221) is connected to the effluent end of the flocculent sludge biochemical reaction zone (21).

6. The continuous flow aerobic granular sludge process system according to claim 5, characterized in that, Includes one or more of the following conditions: B11) The sedimentation tank (221) is connected to the effluent end of the flocculent sludge biochemical reaction zone (21) via a co-current pipe (5); B12) The sedimentation tank (221) is connected to the inlet end of the flocculent sludge biochemical reaction zone (21) via the second return pipe (23); the sedimentation tank (221) is also connected to the second discharge pipe (24). When the sedimentation zone (22) described in B13 is a sedimentator or membrane filter, the sedimentator or membrane filter is located in the area near the effluent end of the flocculent sludge biochemical reaction zone (21).

7. The continuous flow aerobic granular sludge process system according to claim 6, characterized in that, The flocculent sludge biochemical reaction zone (21) is connected to a third return pipe (25) and a third discharge pipe (26). The third return pipe (25) is connected to the inlet and outlet of the flocculent sludge biochemical reaction zone (21) respectively. One end of the third discharge pipe (26) is connected to the flocculent sludge biochemical reaction zone (21).

8. A continuous flow aerobic granular sludge wastewater treatment method, characterized in that, The continuous flow aerobic granular sludge process system according to any one of claims 1-7 includes the following steps: 1) After the wastewater is introduced into the mud-water contact zone of the granular sludge section, it is then introduced into the granular sludge biochemical reaction zone of the granular sludge section. Under the action of the sludge screener, the wastewater undergoes the first separation to obtain the first heavy sludge. 2) The first heavy sludge is returned to the sludge-water contact zone to react with the sewage to form the first mixed liquor; 3) The first mixed liquor is introduced into the granular sludge biochemical reaction zone for the first biochemical reaction, and then separated for the second time under the action of the sludge screener to obtain the second heavy sludge and light sludge. 4) Repeat steps 2) to 3) with the second heavy sludge for the first circulation reflux and then discharge the excess heavy sludge; 5) The second mixture formed by light sludge and sewage is introduced into the flocculent sludge biochemical reaction zone of the flocculent sludge section for a second biochemical reaction. After solid-liquid separation in the sedimentation zone, clear liquid and residual light sludge are obtained, and the clear liquid is discharged. 6) Return the residual light sludge to the flocculent sludge biochemical reaction zone, repeat step 5), and then discharge the excess light sludge after the second cycle of return.

9. The continuous flow aerobic granular sludge wastewater treatment method according to claim 8, characterized in that, Includes one or more of the following conditions: 11) In step 1), the wastewater is introduced into the mud-water contact area through the inlet pipe; 12) In step 1), during the first separation, the sludge separation load of the sludge screen is 3~10 m³ / h; 21) In step 2), the first heavy sludge is returned to the inlet end of the sludge-water contact zone via the first return pipe; 22) In step 2), the reaction time of the mud-water contact reaction is 1-3 hours; 23) In step 2), the mud-water contact reaction is carried out by stirring and mixing, and the stirring method is selected from mechanical stirring or air stirring; 31) In step 3), the first biochemical reaction is selected from one of aerobic reaction or combined reaction, the combined reaction includes aerobic reaction and other reactions, and the other reactions are selected from at least one of anaerobic reaction or hypoxic reaction; 32) In step 3), during the second separation, the sludge separation load of the sludge screen is 3~10 m³ / h; 41) In step 4), the excess heavy sludge is discharged through the first discharge pipe; 51) In step 5), the second biochemical reaction is selected from at least one of aerobic reaction, anaerobic reaction, or hypoxic reaction; 52) In step 5), the clear liquid is discharged through the outlet pipe; 61) In step 6), the residual light sludge is returned to the inlet end of the flocculent sludge biochemical reaction zone via the second or third return pipe; 62) In step 6), the excess light sludge is discharged through the second discharge pipe.

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